Research of Paleontology (ammonoid paleoecology, and taphonomy of fossil-Lagerstätten); Education and supervising for graduate- and post-graduate students; Outreach for citizens; Contribution to academic societies as the councilor and the president (2015—2017).

Shigeta Yasunari, Maeda Haruyoshi, The Cretaceous System in the Makarov area, southern Sakhalin, Russian Far East, National Science Museum, Tokyo, National Science Museum Monographs, No.31, 1—136, 2005.12, The Cretaceous Yezo Group in the Makarov area was closely investigated stratigraphically and paleontologically. The group exposed there ranges from Santonian to Maastrichtian in age, and attains 2,500 m thick in total. It is divided into the Bykov and Krasnoyarka formations in upward sequence. The former consists mostly of offshore mudstones, and is lithologically subdivided into four lithostratigraphic units: B1-B4. The latter is composed mainly of near shore sandstones and deltaic deposits, and is subdivided into five units: K1-K4b. Except for the uppermost part of the Krasnoyarka Formation, the Cretaceous strata are very fossiliferous. Among the fossil fauna, pachydiscid, tetragonitid, and gaudryceratid ammonoids are especially abundant. Sphenoceramus shmidti of the Lower Campanian age also occurs numerously, and forms the characteristic S. schmidti Zone, which is widely traceable throughout the area. It is noticeable that the nearly complete faunal-succession during Campanian and Maastrichtian age is continuously observed there even though internationally stage-diagnostic taxa are few. The sedimentary features of mudstone and the faunal composition of the Yezo Group are similar thoughout South Sakhalin and Hokkaido. Although a few fossil zones obliquely extend over the stratigraphic units, almost identical litho- and biofacies extend over 900 km from south to north. Such depositional- and faunal uniformity reflecting global marine environments in the North Pacific is a remarkable characteristic of the Yezo Group..

Tanaka Gengo, Parker, A.R., YHasegawa Yoshikazu, Siveter, D.J., Yamamoto Ryoichi, Miyashita Kiyoshi, Takahashi Yuichi, Ito Shosuke, Wakamatsu Kazumasa, Mukuda Takao, Matsuura Marie, Tomikawa Ko, Furutani Masumi, Suzuki Kayo, Maeda Haruyoshi, Mineralized rods and cones suggest colour vision in a 300 Myr-old fossil fish., Nature Communications, 10.1038/ncomms6920, 5, 2014.12, Vision, which consists of an optical system, receptors and image-processing capacity, has existed for at least 520 Myr. Except for the optical system, as in the calcified lenses of trilobite and ostracod arthropods, other parts of the visual system are not usually preserved in the fossil record, because the soft tissue of the eye and the brain decay rapidly after death, such as within 64 days and 11 days, respectively. The Upper Carboniferous Hamilton Formation (300 Myr) in Kansas, USA, yields exceptionally well-preserved animal fossils in an estuarine depositional setting. Here we show that the original colour, shape and putative presence of eumelanin have been preserved in the acanthodii fish Acanthodes bridgei. We also report onthe tissues of its eye, which provides the first record of mineralized rods and cones in a fossiland indicates that this 300 Myr-old fish likely possessed colour vision..

Maeda Haruyoshi, Tanaka Gengo, Shimobayashi Norimasa, Ohno Terufumi, Matsuoka Hiroshige, Cambrian Orsten lagerstätte from the Alum Shale Formation: fecal pellets as a probable source of phosphatic preservation, Palaios, 26, 225-231, 2011.04, The Furongian Orsten-type fossil Lagerstätte in the Alum Shale Formation of Sweden is an extraordinary deposit known for its detailed, three-dimensional preservation of the soft parts of small animal carcasses which have been replaced by calcium phosphate and occur in organic-rich nodular limestone. The exact cause and mechanism of this unusual fossil preservation, however, particularly the source of phosphorus, which plays a key role, remains unknown. Detailed observation in the Agnostuspisiformis Zone in the Backeborg section (Kinnekulle district) reveals that the phosphatocopine crustaceans showing soft-part preservation occuronly in a few thin ( 3 cm) layers containing abundant fecal pellets (pellet beds). Development of cross lamination suggests that the pellet beds were formed by low density sediment-gravity flow. Orsten-type preservation has been attributed to high phosphate levels in global marine waters during the Cambrian period; however, wavelength-dispersive X-ray and Xray diffractometry analyses reveal that the Orsten limestones and surrounding shale were generally poor in phosphorus, which was mostly concentrated in the fecal pellets. The small animal carcasses preserved in such deposits were phosphatized during early diagenesis owing to the high local phosphorus levels of the accumulated fecal pellets. Searches for such cesspool-type preservation may yield further discoveries of Orsten-type fossil Lagerstätten in other strata of various ages..

Tsujino Takumi, Maeda Haruyoshi, Maeda Yoko, Taphonomic processes in diatomaceous laminites of the Pleistocene Shiobara Group (caldera-fill, lacustrine), Northeastern Japan, Paleontological Research, 13, 3, 213-229, 2009.09, Diatomaceous laminites of the Pleistocene Shiobara Group (caldera fill), located in the volcanic front of the Northeastern Japan Arc, are the profundal facies ofpalaeo-Shiobara Lake. The laminites are subdivided into five types of laminite: clastic (Type A), diatom-preserved (Type B), porcelainised (Type C), double (Type D) and reversal (Type E). These varieties are mostly induced by lithification, indebted to localised hydrothermal alteration represented as diatom frustules’ transformation from opal-A to opal-CT. Type B laminite alters to Type C, Type D and finally Type E laminites, in a progress order. As alteration is advancing, the rock become more consolidated, and lamina texture changes from porous to massive one. Exceptionally, Type A laminite, composed of grey terrigenous lamina, shows few changes, becauseof poor content of diatom frustules. Type B laminite, composed of porous white diatomaceous lamina and grey terrigenous lamina, is replaced by Type C laminite, composed of tightly-packed opal-CT lepispheres. Type D laminite is represented as a set of four laminae grey, white-1, black, and white-2, in upward sequence. The black laminae result from the additional reprecipitation within the white laminae, and laterally fade. Type E laminite is the last stage of alternation series of the laminites in Shiobara and consists of thin couplets of grey and black laminae. White laminae completely alters to black laminae. Whereas Type A and B laminites is widely distributed in the basin, Type C is distributed in the restricted area. Type D and E laminites are found at only one quarry which yields the exceptionally-well preserved megafossils; mice, frogs, feather, fishes, and insects. These laminite variations are likely derived from alteration by hydrothermal water associated with an caldera..